Its all relative - the Nikon pictures look more processed than the Pentax pictures at high ISOs, but both are a whole lot better than any of the p&amp;s cameras I've seen. The Nikon does do a good job of managing to keep detail while filtering out the noise - Pentax leaves the option up to you to decide how much detail to lose when filtering out noise.

Here's a picture I took Sunday morning at ISO 1600 (I never use 3200 if I can possibly avoid it - the noise is beyond what I'm willing to accept). The only thing special about it is this was the first time we've seen raindrops since April. The picture was taken in raw, converted in ACR, cropped a bit and resized - no other processing, no noise reduction done. There's definitely some noise, but I don't find it all that disturbing, and could easily be dealt with using noise reduction software.

The difference will only be in the JPGs. If you shoot RAW there probably isn't any significant difference in noise levels between the two cameras.

In my experience with the K100D, noise does become visible in shadows at ISO 400 under close inspection. It becomes more obvious at 800, but the images are still good enough to print, and when resized for the web the noise usually disappears. At 1600 the noise becomes rather obvious.

However, if you are willing to spend a bit of extra time on the computer, the noise cleans up well. The Pentax preserves a lot of detail up to ISO 1600, and using software like Noise Ninja you can rather easily clean up your images such that ISO 800 photos look perfectly clean, and ISO 1600 look a bit grainy but still good. Doing it this way also gives you the advantage of having control over how the noise reduction is done and can achieve better results than in-camera noise reduction.

Something I forgot to mention is the fact that noise isn't just a factor of ISO, but also very much dependent on exposure time. Noise builds up over time, so slower shutter speeds lead to more noise, which ironically means that higher ISO settings are more useful in bright light than they are in low light. So, I could show you a picture at ISO 1600 taken in good light that will look practically noise free, and also one taken at night that would make you think the camera was broken.

Here's a shot I just took under a 60 watt bulb. It was shot with a 50mm f/1.7 at f/3.5, 1/20 second:

Yeah, not very interesting, and the white balance is a bit off (which the camera will tend to be under incandescent lighting when using auto white balance).

Here's a 100% crop:

This is pretty much what the camera captured at the pixel level, completely unedited except for the crop. The noise is actually not as bad as I expected, but it's visible in the shadow areas. I guess I'm used to worse noise because I tend to have to turn up the contrast on my photos which makes it much more visible throughout.

Anyway, here it is after a pass through Noise Ninja:

How much difference you see might depend on your monitor, but you could probably see that the small colored blobs have disappeared and the graininess has been reduced. I could have made it even smoother but I prefer a conservative approach to removing luminance noise. I feel too much smoothing makes the image appear somewhat unrealistic.

I hope that was helpful to you. I wasn't expecting to spend that much time on it but sometimes I just enjoy experimenting.

I ended up purchasing the K100D. I got it for $395 shipped so I couldn't really pass up that deal. It should be arriving middle of next week. Needless to say I am very excited as I'll get to use the camera on my pumpkin picking adventure next weekend! Thanks for the quick and extremely knowledgable input everyone.

Long time reader on here, but first time posting. I'm looking to make the jump into the dSLR field and I'm at a loss of what kind of camera to get. To give a uick background, I've been using digital P&amp;S for about 9 years now, and I've always gone with Canon. I shoot a variety of pictures, but mainly landscapes, people, wildlife, cityscapes, etc. At the moment I have an S2 IS, but I'm ready to upgrade. However,I do not like the Rebel lineup at all. It feels flimsy and terrible in my hand.

I believe I have narrowed my choices down to two cameras (possibly three). The Nikon D40, Pentax K100d, or K100d Super. Is the Super worth getting over the regular K100d? I don't feel like I need anything more than 6MP, as I will not be doing enlargements on a regular basis. I like the Nikon as a well known established brand, and I really like the feel of it in my hand. The Pentax grabbed my attention with the fact that it has AntiShake built in and the backwards lens compatibility. I've seen sample pictures from both and both look great. On my S2, my IS comes in handy ALL THE TIME, so I think this would make me lean more towards the Pentax.

Any thoughts or input would be greatly appreciated. Thank you!

As the other said, both camera has its own advantages and dissadvantages. Nikon has a little longer experience in photography, but I think Pentax DSLR will much more fits your needs.